572 



BULLETIN OF THE BUREAU OF FISHERIES 



promontory. The Fish Hawk, also, made a general survey of Massachusetts and 



Cape Cod Bays on June 16 and 17 in 1925. A few temperatures were taken by the 



Halcyon near Glouces- 

 Temperature, Centigrade 



9° 10° ir 12° 13° 



Meter 



10 



20 



30 



40 



50 



60 



70 



80 



90 

 100 

 110 

 120 

 130 

 140 

 150 

 160 

 170 

 180 

 190 

 200 



Fio. 38.— Vertical distribution of temperature on the southwestern slope of Georges Bank to 

 show cooling of the bottom water, but warming at the surface, from Febiuary to May, 

 1920. A and B, February 22 (stations 20046 and 20045); AA and BB, May 17 (stations 

 20128 and 20129) 



illustrate interesting regional differences in the rate at which heat penetrates down- 

 ward into the water during the late spring and early days of summer, depending 



ter on the 6th in 1924, 

 in the Nantucket 

 Shoals region during 

 the first half of the 

 month in 1925, and 

 Dawson (1922) also 

 took a considerable 

 number of June read- 

 ings along Nova Scotia 

 in 1904 and 1907. 



RATE OF WARMING 



Progressive warm- 

 ing is to be expected, 

 of course, over the 

 whole area throughout 

 the month of June. 

 Thus, the surface had 

 warmed to 10.56° at 

 a station 8 miles off 

 Gloucester on the 6th 

 in 1924, and to 12.1°- 

 15.2° over Massachu- 

 setts Bay generally 

 by the 16th or 17th in 

 1925, an average 

 change of about 5 

 degrees since May 20 

 to 22. At the 20- 

 meter level these mid- 

 June temperatures 

 averaged about 7.8° 

 (IS stations), contrast- 

 ing with about 5.5° 

 in May (p. 564), with 

 the readings for June 

 6, 1924 (6.2°) inter- 

 mediate, as the date 

 would suggest. These 

 Massachusetts Bay 

 stations for 1925 also 



